Gunsmith Katsumi - Akitsukuni Arms Design Quest

[Eukie]

Tachibana Katsumi

Stress: 5/10

Accomplishments
Mechanical Engineering degree
Got a job in your field
Type 37 Special Purpose Rifle
Type 38 Self-Loading Pistol

Friends
Maeda Rumi: Your roommate.
Sanders Clara Rose: A colleague who works for Naylor, Sons & Daughters.

Coworkers
Mr. Watanabe: Your superior.
Mr. Akutagawa: The boss of the company.

Workshop 3
Ms. Ikeda Nioh: Chemist. She also seems to be Mr Watanabe's personal secretary, but you're not sure if that's an official position.
Mr. Yakade Yasuo: Physicist, specialized in ballistics. A living, breathing Technical Appendix C.
Mx. Kusonoki Mayumi: Has a degree in materials science. Gets a look on their face when they say they know more about wood than anyone.
Mr. Shiragiku Hideyoshi: Metalworker. Having met him, you've learned why metalworking is a craft and the meaning of the phrase "thinks himself heaven's gift to women".
Mr. Kashiwa Ichiro: An apprentice gunsmith with a background in carpentry and actually using guns on people.

Technologies

Spoiler: Technologies

Rifles (Familiar)
Shotguns (Familiar)
Pistols (Familiar)

Rotate-and-pull bolts (Practical)
Straight-pull bolts (Practical)
Aperture sights (Practical)
Stripper clips (Practical)
Lever-delayed blowback operation (Practical)
Double-stack magazines (Practical)
Single-action handguns (Practical)
En bloc clips (Conceptual)
Simple blowback operation (Conceptual)
Short recoil operation (Conceptual)
Toggle-delayed blowback operation (Conceptual)
Blow forward operation (Conceptual)
Simple blowback operation (Conceptual)
Double-action pistols (Conceptual)
Automatic revolvers (Conceptual)

 

[Sarpedon]

I mean if it only needs 20-40 meters of range how much would it weight?

Click to shrink...

Assuming you went cup discharger because you want to have a usable pistol afterwards and assuming you could make one only 1/3rd the weight of rifle equivalents it would still weigh around 500g.

EDIT: Also at this point its past the point of diminishing returns because you would have a small projectile with very little HE with a large recoil and high weight.

 

[thepsyborg]

[X] Interesting!
[X] Automatic
-[X] Attempt an underbarrel clip-on mount with optional "20-gauge masterkey" and "ridiculous bayonet" attachments
[X] Common Calibre - Write In: Vyborg 8mm

We're a long way from universal pistol tacrails, but maybe we can invent their great-granddaddy.

 

[Skippy]

[X] interesting!

[X] Automatic
-[X] Common Calibre - Write In: 7.63 Katzen

I for one welcome our new firearm feline overlords

 

[Gnarker]

For the uninitiated, what actually is the difference between 7.63 and 8mil?

 

[googlyeyesultra]

7.63 is bigger, so we'll probably fit one or two less in the magazine. It's a higher energy round, which has some plusses and minuses (better range, more power, need a stronger action). The projectile (bullet) is lighter, which I think the army won't like.

7.63 is supersonic I think, so it'll also be a fair bit louder.

 

[Sarpedon]

For the uninitiated, what actually is the difference between 7.63 and 8mil?

Click to shrink...

7.63 is flatter shooting and higher velocity with more muzzle energy but less recoil because it is a less massive projectile and therefore has less momentum and a lower recoil impulse back at the shooter. 8mm is a heavier bullet that goes slower and is slightly thinner on the whole as a cartridge, which can help with magazine width and width of the actual pistol.

 

[googlyeyesultra]

but less recoil because it is a less massive projectile and therefore has less momentum and a lower recoil impulse back at the shooter.

Click to shrink...

Are you sure it's lower recoil? Just multiplying the muzzle velocity by the bullet mass would give the 8mm a lower recoil (lower velocity makes up for the higher mass) but I'm not sure if that's how you calculate it.

 

[firestorm440]

Recoil's tricky to measure, because theoretically it's just F=ma but perceived recoil is also strongly affected by the weight and design of the gun.

 

[Eukie]

Recoil, in particular the kind of recoil used to measure how gentle a pistol is to fire, is typically the "free recoil", which a measure of energy proportional to the square of the momentum of the bullet and powder, divided by the weight of the firearm. The difficulty in that calculation is determining the velocity of the powder, which often contributes about half the total energy in the final calculation, which makes it troublesome to leave out. Various sources will suggest various approximations: guns.wikia suggests 1707 m/s as the velocity of pistol powders, while the British Text Book of Small Arms apparently suggests 1.5 times the muzzle velocity.

 

[coyote16able]

[X] ... interesting.
[X] Revolver
-[X] Common Calibre - Write In: .38 Special

 

[7734]

For Army it's going to be a secondary weapon. For Navy it's going to be a primary one. So in theory we should focus on Navy requirenments and not on Army. Buuuuuuut if we do that, Army judges (Army's men in commitee or whoever is the deciding body here) will give us 0 points out of spite. So we should try to balance both armed forces requirenments or politics will kill our superior gun.

Click to shrink...

Shotguns are normally 12 or 20 gauge in this time period. Flares are 37mm or so. The following picture is a 25mm flare gun.



As you can see, this is not going to fit under a pistol barrel without some creative geometry.

For Army it's going to be a secondary weapon. For Navy it's going to be a primary one. So in theory we should focus on Navy requirenments and not on Army. Buuuuuuut if we do that, Army judges (Army's men in commitee or whoever is the deciding body here) will give us 0 points out of spite. So we should try to balance both armed forces requirenments or politics will kill our superior gun.

Click to shrink...

Don't bet on that- we may still well be in the era where cavalry are pistol-and-saber, although I doubt it. This will certainly be the primary arms of artillery and logistics branches, though.

How did I go to sleep dreaming of a Mauser C96 with removable magazine and optional Schnellfeuer conversion and wake up to a revolver/shotgun/flare gun/grenade launcher/literal handcannon firing HESH?

Click to shrink...

It's magic. The QM ain't gotta explain shit.

 

[Strypgia]

Everyone trying to slap a flare/shotgun load onto this, keep in mind: There's a 1000g weight limit to this, and most of the weapons we're looking at copying/stealing features from are already over that limit before adding extra heavy bits. This is a pistol, not a machine pistol or carbine.

 

[Always Late]

we may still well be in the era where cavalry are pistol-and-saber, although I doubt it.

Click to shrink...

But there'll be people in the army who remember those days. There were American Civil War veterans still alive in 1914, so there may still be veterans of a not!Boshin War or Samurai rebellions in the higher ranks of the officers and generals.

Nostalgia and antiquated ideas for weapons have been a bit of a theme here.

Everyone trying to slap a flare/shotgun load onto this, keep in mind: There's a 1000g weight limit to this, and most of the weapons we're looking at copying/stealing features from are already over that limit before adding extra heavy bits. This is a pistol, not a machine pistol or carbine.

Click to shrink...

Maybe make the chambers and barrel easily interchangeable? I have no idea how the barrel would be done though.

 

[7734]

But there'll be people in the army who remember those days. There were American Civil War veterans still alive in 1914, so there may still be veterans of a not!Boshin War or Samurai rebellions in the higher ranks of the officers and generals.

Click to shrink...

I'm thinking more like mid 70s and 80s really; not some 50/60s affair. Cavalry were seriously armed with repeating pistols as their primary weapons for quite a while in Continental armies explicitly because it let them coat an area in lead one-handed and was a solid weapon for skirmish actions during recce missions. There's a non-zero chance this logic prevails, but there's also a very good chance that a War In China/Russia has made people realize that the terrain does not favor this approach and are breaking out the cavalry carbines.

That said given the less than optimistic Russian performance I distantly remember from the Planes Quest, "charge them down while the QF guns suppress them" might very well still work.

 

[Gnarker]

7.63 is flatter shooting and higher velocity with more muzzle energy but less recoil because it is a less massive projectile and therefore has less momentum and a lower recoil impulse back at the shooter. 8mm is a heavier bullet that goes slower and is slightly thinner on the whole as a cartridge, which can help with magazine width and width of the actual pistol.

Click to shrink...

So recoil is complex and can be mitigated, and in a pistol I'd expect overall accuracy to become the limiting factor long before bullet drop does. Leaving the magazine size like it should be the deciding factor. Am I missing anything?

 

[Always Late]

I'm thinking more like mid 70s and 80s really; not some 50/60s affair. Cavalry were seriously armed with repeating pistols as their primary weapons for quite a while in Continental armies explicitly because it let them coat an area in lead one-handed and was a solid weapon for skirmish actions during recce missions. There's a non-zero chance this logic prevails, but there's also a very good chance that a War In China/Russia has made people realize that the terrain does not favor this approach and are breaking out the cavalry carbines.

Click to shrink...

Considering cavalry was still being used in 1918 on the Western Front for shock and exploitation, despite the insatiable need in the Middle Eastern theaters for mobile forces?

Never underestimate the power of the Hide-bound Cavalry Lobby.

 

[7734]

Considering cavalry was still being used in 1918 on the Western Front for shock and exploitation, despite the insatiable need in the Middle Eastern theaters for mobile forces?

Never underestimate the power of the Hide-bound Cavalry Lobby.

Click to shrink...

You're thinking at entirely the wrong level, and your example is actually pretty trash since at that point the cavalry regiments deployed to Europe were very badly "de-horsed", so to speak, due to the fact they went through horses faster than men- and there was a far smaller store of replacement horses. By 1916, the armies were dipping into breeding stock; by '18 the herd was at minimum population to still have a heard after the war.

As to armament, the main reason for the conversion to carbines and the debate on them had nothing to do with hidebound officers so much as the expected battle conditions of the day. After QF guns got the shell and fused canister, the concept of the Glorious Charge died hard; that said though melee action was still quite common. What decided things for the carbine or the pistol was simply the odds of the cavalry serving as dragoons- that is, soldiers mounted for transit and fighting on foot. Dragoons likely, get carbine. If not, get pistol. Most countries had splits between the former and later- often called curiasirs, uhlans, or hussars- which gave them the best of both worlds.

Hidebound officers aren't really a problem here. This is entirely a doctrine issue: and given what we've seen so far, I'm willing to say the cavalry doctrine is unlikely to be wrong. Artillery and motorized use? Probably fucked, IMO. Not cavalry, though.

 

[Sarpedon]

So recoil is complex and can be mitigated, and in a pistol I'd expect overall accuracy to become the limiting factor long before bullet drop does. Leaving the magazine size like it should be the deciding factor. Am I missing anything?

Click to shrink...

I would argue that having a flat shooting cartridge is something that makes shooting accurately easier, especially when one one of the core requirements is "give us a shoulder stock to turn this into a carbine so we can make people shoot it at longer ranges." Otherwise however, given the hard 1kg limit I don't actually think we will be able to squeeze more than 1 extra round of 8mm in compared to 7.63, even in a larger handgun and given that early semiautos are generally going to be carried in Condition 2 you may not even have a practical difference in # of rounds in the gun.

 

[FrangibleCover]

The Type 15A uses the forearm of the Type 15 Cavalry Carbine, with five shots instead of eight. If this pistol was going to be a primary weapon for the cavalry it would have been noted.

 

[Gnarker]

I would argue that having a flat shooting cartridge is something that makes shooting accurately easier, especially when one one of the core requirements is "give us a shoulder stock to turn this into a carbine so we can make people shoot it at longer ranges." Otherwise however, given the hard 1kg limit I don't actually think we will be able to squeeze more than 1 extra round of 8mm in compared to 7.63, even in a larger handgun and given that early semiautos are generally going to be carried in Condition 2 you may not even have a practical difference in # of rounds in the gun.

Click to shrink...

Hmm. This feels like something we'll likely need numbers for.
- What is the useful accurate range of a pistol carbine?
- Over that range, how much bullet drop does 8mm get?
and
- How much do 8mm and 7.63 cartridges weigh?

Anyone know the answers to these? Wikipedia is giving me loads of dimensions for the cartridges, but not weight.

Edit: Apparently the Artillery Luger was sighted to 800 meters.

 

[Eukie]

Welp, votes are tied between 8 mm Vyborg and 7.63 mm Katzen, so we're inviting everyone to help decide between the two!

[X] interesting!
[X] Automatic

You're sketching designs for automatic pistols in your notebook, trying out various configurations and thinking of ideas for getting around various patents. When you turn to magazine design you doodle a few setups inspired by what you've seen, but eventually you have to grab Yadake.

"What have you found in terms of small calibre pistol rounds?" you ask.

"How small are we talking? There's nine millimeter Palten..."

"Too big. Eight mil at most." you fire off. You add: "At least three hundred Joules."

"That narrows it down a lot." Yadake raises an eyebrow. "In that range there are only two calibres I think are worth pursuing. Seven six three Katzen and eight mil PAP."

"Advantages and disadvantages," you say, as you draw a table in your notebook, with one column labeled 'Katzen' and the other 'PAP'.

"Katzen is small, fast—it's supersonic—and powerful, but the cartridge is pretty big: about a milimeter wider and over five mils longer. The PAP has a more compact cartridge but the bullet is slower and heavier. Comparing the two, the cartridge weigh is the same, PAP has..."

Yadake thinks for a bit. You can tell from how small grimaces makes his mustache wriggle that he's doing a lot of mental arithmetic.

"Twenty percent less muzzle energy, thirteen percent less recoil, fifty percent more drop at range, and twenty percent less drift due to wind."

"Thanks, Yadake," you say and turn to your two columns:

7.63 mm Katzen    8 mm PAP
Fast              Smaller cartridge
(Loud)            Heavy
Powerful          Less recoil
Less drop         Less wind drift

You tap your pencil against the page as you think. You're not sure: more bullets in the magazine and a bullet more likely to kill with the first shot are both nice up close, and at range both less drop and less wind drift are good. You feel a pang of sympathy for Yadake: it would be really fun to make a cartridge that takes the best of both worlds.

Still, you can't get lost in fantasies: you have a decision to make.

So which'll it be?

[ ] 7.63x25 mm Katzen​

[ ] 8x19 mm Palten Armée Pistole​

 

[Sir_Travelsalot]

[X] 8x19 mm Palten Armée Pistole

 

[sith1144]

[X] 8x19 mm Palten Armée Pistole

Don't think the range matters much at pistol range. More power is nice but less recoil means it's easier to put multiple rounds on target which will compensate for a bit less power, I think.

 

[veekie]

[X] 7.63x25 mm Katzen

Navy or army I don't think wind drift or noise is a thing by the time you're down to a pistol.

 

[NothingNow]

[X] 7.63x25 mm Katzen